The Fort of Santa Catarina is a medieval fort situated in the civil parish of Portimão, in the municipality of Portimão in Portuguese Algarve. The structure was considered one of the last Philippine military projects in the Algarve, erected to defend the peninsula from pirates and privateers, as well as military invasions. Its construction is one of the better examples that work of Alexandre Massai, a military engineer who toured the Algarve to reinforce numerous military fortifications along the coast.